Spatial differences across the French Pyrenees in the use of local habitat by the endangered semi‐aquatic Pyrenean desman (Galemys pyrenaicus)

Abstract

ABSTRACT1. The implementation of effective and appropriate protection actions is frequently hindered by lack of thorough knowledge on species ecology especially in the case of endemic, vulnerable and elusive species.2. Using a recently updated and unpublished dataset describing the spatial distribution of the Pyrenean desman (Galemys pyrenaicus) in its northern range (French Pyrenees), an Ecological Niche Factor Analysis (ENFA) was conducted to provide a quantitative estimate of local habitat use by this endangered semi-aquatic mammal. A comparative approach was used to investigate potential differences in habitat use among the three main hydrological regions of the French Pyrenees.3. The Pyrenean desman was identified as a marginal and specialist species concerning the selection of its local habitat in the French Pyrenees. Key habitat variables corresponded mainly to river-bed characteristics (i.e. high heterogeneity of shelters and river substrates, fast flowing water facies, low amounts of fine sediment) and river-bank characteristics (i.e. high proportion of rocks, low proportion of earth). A difference in habitat selection between the three hydrological regions of the French Pyrenees was also highlighted. A decrease in marginality and specialization from west to east as well as differences in habitat variables driving the ecological niche of the Pyrenean desman and its range suggested a spatial structure in desman populations regarding local ecological factors.4. These results stress the importance of effective and sustainable river management for the habitat quality of this endangered species and also demonstrate the importance of taking into account the variability in habitat preferences that can exist between geographically distinct populations. This finding has important implications for conservation planning that should thus be conducted at the population level instead of the traditional species level in order to target the specific needs of each hydrological region.

Need for speed: Preference for fast‐flowing water by the endangered semi‐aquatic Pyrenean desman (Galemys pyrenaicus) in two contrasting streams

“…Stream flow velocity has been reported as an important environmental factor for the Pyrenean desman (Charbonnel et al, ). Biffi et al () performed an Ecological Niche Factor Analisys (ENFA) based on the detection of faeces. They concluded that the habitat of the Pyrenean desman is characterized by in‐stream variables (substrate heterogeneity, fast‐flowing water, absence of fine sediment), as well as by bank characteristics (rocky banks), with desmans preferring sites with abundant emergent structures and a high heterogeneity of shelters.…”

“…Desmans usually shelter in natural crevices between rocks, in stone walls, or below the roots of riparian trees; usually there are no outwardly visible signs of the shelters from the surface (Stone, ). They feed mainly on freshwater invertebrates (Biffi et al, ; Santamarina & Guitian, ). Many factors can affect freshwater invertebrate abundance and composition, from pollution to drought, or changes in physical habitat (Cowx, Young, & Hellawell, ; McIntosh, Benbow, & Burky, ; Wood, Agnew, & Petts, ).…”

“…Morueta‐Holme, Fløjgaard, and Svenning () highlighted the importance of discharge, as more water offers better habitat conditions and greater food availability. Biffi et al () provided information about habitat factors measured at the local scale in river stretches occupied by desmans, but did not provide information about factors controlling occupancy at the microhabitat scale: key information for understanding the needs of desman. Moreover, as habitat selection patterns change spatially according to differences in habitat availability (Ayllón, Almodóvar, Nicola, & Elvira, ; Boyce et al, ), it is necessary to study the behavioural response of desmans in contrasting environments to understand better the key factors shaping their habitat preferences.…”

Comparison of diet and prey selectivity of the Pyrenean desman and the Eurasian water shrew using next-generation sequencing methods

“…The alarming decline of G. pyrenaicus populations over the recent decades across its whole range Gisbert and García-Perea, 2014) has encouraged local, national and European conservation initiatives (e.g., in France: Life+ Desman, 2013;Némoz et al, 2011). Yet, in spite of an increasing number of studies focusing on this species (e.g., Aymerich and Gosàlbez, 2015;Biffi et al, 2016;Charbonnel et al, 2016;Escoda et al, 2017), the respective influence of prey, competitors and predators on its survival and distribution still remains to be explored.…”

Regresión reciente y general del desmán ibérico en su límite noreste de distribución

“…Hasta ese momento, se asumía que el desmán había experimentado regresiones locales y regionales, pero los datos disponibles eran escasos. Poco después se publicaron los resultados de una actualización general de la distribución del desmán en los Pirineos franceses (Biffi et al 2016, que reflejaban también una marcada regresión de la especie en las dos últimas décadas, si bien en Francia hubo algunos cambios metodológicos entre las prospecciones de los años 1980-1990 y las recientes (no se muestrearon tramos idénticos y en la segunda prospección sólo se consideraron positivos los indicios confirmados genéticamente). Estudios recientes llevados a cabo en otras zonas del área de distribución del desmán (por ejemplo Fernández et al 2014Fernández et al , 2017 sugieren igualmente una cierta regresión pero estos datos son poco comparables con los procedentes de los Pirineos, porque las informaciones utilizadas son más heterogéneas.…”